cfherrman
TFP Guide
Which spot? Circle it in red if you can
Stab = insert
This is the capped off vac port? If so, the problem with having that as a suction is it kills your skimmer, main drains have this problem as well. So you will find out that you will be leaving the vac port closed all the time.
If this was my pool I would want the water to be circulated in the line but I would never plan on using it. I would plum it it, plug the line in the pool but drill a small hole in the plug that a trickle of water flow through it, then you do have a vac port if you want.
Yes a lot of work for very little gain, if you don't have experience in stabbing two connections at once I would not as if you miss it your next option to fix it will be pulling the valve.